Funding for this research was provided by:
Japan Society for the Promotion of Science (JPI5H0Z90I)
Smoking Research Foundation
Received: 15 January 2020
Accepted: 18 February 2020
First Online: 3 April 2020
Ethics approval and consent to participate
: Ethical approval for the study was obtained by the ethics committee of the National Hospital Organization Kyoto Medical Center (approval number: 15-067; approval date: September 20, 2015). All participants provided written informed consent for research. No individual level data is being reported in this manuscript.
: Not applicable.
: The authors declare that they have no competing interests.